摘要
设计一种适用于单个光伏组件的光伏并网微型逆变器,拓扑结构主要包括交错并联反激变换器、全桥反转电路和LC滤波电路。分析反激逆变器的工作原理和实现条件;采用数字信号控制器实现交错并联反激逆变器的软开关控制,可减小功率器件开关损耗,提高逆变器电能转换效率;改进的变步长扰动观察法,解决跟踪速度与控制精度之间的矛盾。通过样机实验验证设计的单级式光伏并网微型逆变器具有体积小、输出谐波含量低、功率密度高和电磁兼容性好等优点。
A photovoltaic( PV) grid-connected microinverter suitable for a single PV module and the topological structure mainly consists of interleaved flyback converter, full-bridge inversion circuit and LC filter circuit. The working principle and realization conditions of flyback converter is analyzed; the digital signal controller is adopted to realize soft switching control of the interleaved flyback inverter, reduce the switching loss of power devices and improve the conversion efficiency of electrical energy of inverter;the improved perturbation and observation( P & O)method based on variable step size is employed to resolve the conflict between tracking velocity and control precision. The prototype test is conducted to verify that the single-stage grid-connected PV microinverter has the following advantages: small volume, low output harmonic content, high power density and good electromagnetic compatibility(EMC), etc.
引文
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